Knife sharpening device



July 26, 1938. G. BARSCH KNIFE SHARPENING DEVICE 2 Shets-Sheet 1 Filed Feb. 8, 1936 July 26, 1938. G. BARSCH KNIFE SHARPENING DEVICE Filed Feb. 8, 1936 2 Sheets-Sheet 2 Gu/ //au rne 60/30 7 Patented July 26, 1938 UNITED STATES PATENT FFEQE KNIFE SHARPENING DEVICE Guillaume Barsch, Paris, France, assignor to Industrie A. G. Allegro, Emmenbrucke, Switzerland 7 Claims.

The present invention relates to knife sharpeners.

The principal object of the invention is to provide a knife sharpener which will sharpen 5 knife blades with uniform eniciency, and which is readily adaptable for knife blades of varying Widths.

Other objects and advantages of the invention Will be apparent from the following drawings wherein,

Figure 1 is a side elevation of a knife sharpener constructed in accordance with my invention, portions of the base being broken away;

Figure 2 is a plan view of the knife sharpener of Figure 1;

Figure 3 is a view similar to Figure 1 showing the knife sharpener in use;

Figure 4 is a side view of a modified form of knife sharpener;

Figure 5 is a plan view of the knife sharpener of Figure 4;

Figure 6 is a detailed side elevation showing the position of the sharpeningv elements of the Figure 4 device, and

Figure 7 is an end view of the blade supporting element used in the Figure 4 construction.

Referring to Figures 1 to 3, the knife sharpening device there illustrated comprises a base or support I which may be formed of wood or the like and which is provided with two relatively offset cutout portions la extending longitudinally thereof and each terminating at a point adjacent the median line of the base. Plates 2 and 2a are positioned on the upper side of the base I, each 3 of the plates covering one of the cut-out portions la. The plates are respectively provided at their inner ends with pivots 6 and 6a to support grindstone holding elements 4 and 4a respectively.

Above the pivot points 6 and 6a, the holding elements have fixed therein oppositely facing grindstones and 5a. The grinding surfaces of the stones are concaved as shown in Figure 1 in order that the angle of the stones with respect to the edge of the blade presented therebetween will always be the same. Beneath the pivot points, the grindstone holding elements 4 and 4a have springs 3 and 3a, respectively, connected thereto, the outer ends of the springs being connected to depending angled portions on the plates 2 and 2a. By this arrangement, the stone holding elements and the stones themselves will be tilted to the position shown in Figure l to thereby exert a proper pressure against a knife blade positioned between the stones.

A slot or kerf 9 extends transversely through the base or support I, this slot being properly centered between the pivot points 6 and 6a. A knife supporting element l having the form of an eccentrically mounted roller is positioned in the slot, the element 1 being rotatably mounted by means of journals carried thereby which extend into sockets 3 on the opposing faces of the slot. The periphery of the roller 1 may be covered with rubber, felt or the like.

If desired, the pivot points 6 and 6a may be positioned above the point shown on Figure 1, in which case the grinding surfaces of the stones 5 and 5a would be convex instead of concave;

By the arrangement shown in Figures 1 to 3, a knife blade, indicated by the numeral [8 in Figure 3, may be inserted between the grindstones 5 and 5a, the back of the blade resting upon the eccentrically mounted roller 1 and the springs 3 and 3a holding thesurfaces of the grindstones pressed against the cutting edge of the blade with uniform pressure. As the knife blade is moved transversely between the stones, it will be moved vertically by the rotation of the supporting roller 7 upon its eccentrically positioned journals, these two motions resulting in a wave line producing a diagonal grinding motion which has the most effective sharpening action, with the advantage that the sharpening takes place along constantly changing generating lines of the sharpening surfaces, thereby preventing the edge of the blade from cutting into the stones.

It will be observed that the provision of concave faces upon the grindstones and the spring mounting thereof will cause the stones to act at the same angle with respect to any knife blade presented between the same, regardless of the width of the blade.

Referring to Figures 4 to '7, the form of my device disclosed therein comprises a base or support H having a suitable housing l2 of sheet metal or the like secured to its upper portion. The housing i2 encloses grindstone holding elements i 3, which are arranged parallel but offset with respect to each other. Grindstone elements l4 are mounted upon the opposing or inner faces of the holding elements l3, as shown in Figures 4 and 6, thestones overlapping opposite a slot l5 provided in each side wall of the housing 52. The grindstone holding elements 13 are tilted to the 50 position shown in Figure 4 by a coil spring l5 arranged within a rib ll extending longitudinally of the top of the housing, the ends of the spring being secured to the free ends of blades 58 having their lower ends pivotally connected to the base l l. Intermediate their ends, the blades l8 are provided with offset portions l 9 which bear upon the rear faces of the grindstone holding elements IS, the entire arrangement being such that both elements will be uniformly pressed toward each other.

In order to permit the holding elements to be moved apart to permit of the insertion of a knife blade between the same, each holding element is provided with a tang 20 which projects through an aperture in the upper wall of the housing 12.

Pressure upon the tangs 20 in the direction of the arrows shown in Figure 5 will obviously cause the grindstones I4 to be moved apart.

A slot or kerf 22 is provided in the base II in alignment with the slots I2 in the housing so that a knife may be readily presented to the grindstones. An eccentrically mounted roller 23 is positioned in the slot 22, and in order to enable this roller to be positioned at varying distances with respect to the grindstones M, a plurality of sockets 24 open from the near edge of the base I l, as seen in Figure 4, these sockets being adapted to selectively receive the eccentrically positioned journals 25 of the roller 23. A plate 26 is slidably secured to the same side face of the base II, this plate being provided with a vertically extending slot 21 having horizontal slots 28 opening therefrom and substantially corresponding in size with the sockets 24. When the plate 26 is in the position shown in Figure 4, the slots 28 of the plate will be out of alignment with the sockets 24 but when the plate is raised, the slots and sockets will be in alignment so that the roller 23 may be positioned as desired and in accordancewith the thickness of the knife blade to be sharpened. The roller 23 preferably has its periphery covered with rubber, felt or the like. The construction as shown in Figures 4-7 thereby provides a device which may be readily adapted to handle knife blades of varying widths.

It will be observed that both forms of my invention include the means to reciprocate a knife blade vertically while it is being moved between the grindstone elements, and that both devices are readily adjustable for knife blades of various widths, but will nevertheless exert grinding pressure upon the knife edge at a uniform angle, regardless of the width of the blade being sharpened between the stones.

I claim:

1. In a knife sharpening device, the combination of a base and a grinding element, and means to support a knife in moving contact with said element comprising a roller journaled on said base for rotation during movement of the knife, said roller being eccentrically mounted on its journal.

2. The combination in a blade sharpening device, of a base, a grinding element movable in a predetermined direction with respect to said base and having a grinding face inclined with respect to said base, and a blade supporting element rotatably mounted in said base to movably support a blade in angled contact with the grinding face of said grinding element, said supporting element being mounted to have an eccentric movement with respect to said grinding element.

3. The combination in a blade sharpening device, of a base, a grinding element slidable in a predetermined direction with respect to said base and having a grinding face inclined with respect to said base, and a blade supporting element rotatably mounted in said base to movably support a blade in angled contact with thegrinding face of said grinding element, said supporting element being mounted to have an eccentric movement with respect to said grinding element.

4. The combination in a blade sharpening device, of a base, a grinding element pivoted on said base for swinging movement in a predetermined direction with respect to said base and having a grinding face inclined with respect to said base, and a blade supporting element rotatablymounted in said base to movably support a blade in angled contact with the grinding face of said grinding element, said supporting element being mounted to have an eccentric movement with respect to said grinding element.

5. The combination in'a blade sharpening device, of a base, a pair of grinding elements movable relative to each other and in a predetermined direction with respect to said base and having opposed grinding faces inclined with respect to said base, and means to support a blade in angled contact with the grinding faces of said elements and to bodily move the blade longitudinally of the grinding faces of said grinding elements, said means also functioning to simultaneously move the blade in a plane substantially at right angles to the direction of movement of said grinding elements to move said grinding elements along their path of movement.

6. The combination in a blade sharpening device, of a base, a pair of grinding elements movable relative to each other and in a predetermined direction with respect to said base and having opposed grinding faces inclined with respect to said base, means to support a blade in angled contact with the grinding faces of said elements and to bodily move the blade longitudinally of the grinding faces of said grinding elements, said means also functioning to simultaneously move the blade in a plane substantially at right angles to the direction of movement of said grinding elements to move said grinding elements along their path of movement, and resilient means tending said grinding elements toward the blade supporting means.

. 7. The combination in a blade sharpening device, of a base, a grinding element movable in a Ill) predetermined direction with respect to said base and having a grinding face inclined with respect to said base, means rotatably mounted in said ,base to support a blade in angled contact with the grinding face of said element, said supporting means being so mounted in said base that upon rotation thereof it will bodily move the knife longitudinally of the grinding face of said grinding element and in a direction substantially at rightangles to the direction of movement of said grinding element to move said grinding element along its path of movement.

GUILLAUME BARSCH. 

